Finding certain standing stances disrespectful is definitely not universal; I've trained in a number if dojo where it was simply expected you would be quiet and attentive. Ditto falling into seiza when the instructor is working with one pair of training partners; many dojo have a policy that, as the instructor is actively moving among groups, the other students should continue training or else no training would take place.
No right or wrong, just observing norms and "when in Rome"...